The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Referring now to FIG. 1, a functional block diagram of a communications system 102 is presented. User equipment (UE) 104 establishes connections with a 3rd generation partnership project (3GPP) network 106 and a non-3GPP network 108. The non-3GPP network 108 maintains a communications link with the Internet 110. The 3GPP network 106 may establish links with other user equipment and provide communication between various user equipment, including the user equipment 104.
The 3GPP network 106 may maintain a link with the public switched telephone network (PSTN) 112 and/or other service providers 114. The other service providers 114 may also maintain 3GPP networks. For example only, the user equipment 104 may include a mobile phone or a laptop with voice capability. The user equipment 104 may transmit and receive packet data to and from the Internet 110 via the non-3GPP network 108. For example, the user equipment 104 can display web pages from the Internet 110 via the non-3GPP network 108. The user equipment 104 transmits and receives circuit-switched voice data over the 3GPP network 106.